Radar apparatuses are currently used in various fields. One such radar apparatus is a type of radar apparatus that is referred to as a dual-frequency continuous wave (CW) radar. The dual-frequency CW radar has a higher detection sensitivity for speed compared to a frequency-modulated continuous wave (FMCW) radar. In addition, the dual-frequency CW radar is useful in detection of a target that has low reflection intensity, such as a pedestrian. Also, the dual-frequency CW radar is capable of detecting even a small target as long as the target has speed. Therefore, the dual-frequency CW radar is known to also detect clutter, such as rain and snow, that does not require detection. Here, clutter refers to unnecessary reflected waves that are generated as a result of radio waves from a radar being reflected by a sea surface, rain, or the like.
A technology is known in which the presence of such clutter is determined based on variations in the power level of reception signals (refer to, for example, PTL 1). The above-described technology takes advantage of the fact that, whereas power variation of a target to be detected (such as a ship on the sea) is large, power variation of rain/snow clutter (unnecessary reflected waves generated as a result of reflection by rain, snow, and the like) is relatively small.